The Diary of Kido Takayoshi was a translation of his diaries done by Sydney Devere Brown and Akiko Hirota. It was published in 1983-1986 as 3 volumes/
Volume 1 covers the years 1868-1871.
Volume 2 covers 1871-1874.
Volume 3 covers the years 1874-1877.
These are not in print and difficult to track down. I was able to access these volumes while enrolled in a graduate institution. I read through and selected entries that spoke to my specific interests in Choshu personages, illustrated aspects of his political/life philosophy, and also focused on his poetry.
I stopped with the Iwakura Mission in Volume 2 as I lost access to those books and believe that the content of that mission has been well-covered by other books available in print.